This invention relates to a process for making adducts via the reaction of olefins, including polyolefins, with dimeric thionophosphine sulfides, the products of said process, various derivatives thereof, and use of said products and derivatives as lubricating oil and fuel additives.
It has been known that phosphosulfurized hydrocarbons, such as olefins, particularly polyisobutylene, reacted with phosphorus pentasulfide (P.sub.2 S.sub.5) can exhibit detergent effects in lube oil and fuel, as well as oxidation inhibition properties. However, while various phosphosulfurized hydrocarbons have been known in the art (J. R. van Wazer, Phosphorus and Its Compounds. Interscience Publishers, Inc., New York, 1961, Vol. II, p. 1276-1277), in general they are acidic and usually are complex and undefined products which vary in composition depending on reaction conditions and reagent ratio. Also, they frequently undergo hydrolytic degradation to give corrosive, inorganic phosphoric and thiophosphoric acids (e.g., see U.S. Pat. No. 3,185,728). Neutralization of these acidic P.sub.2 S.sub.5 hydrocarbons, with metallic and amine bases, frequently engenders low molecular weight metal and amine thiophosphate salts, which salts in turn, are potential sources of sludge and sediment, tending to adversely affect any detergent properties otherwise present. Contrary to many of the prior phosphosulfurized hydrocarbons, the process of the present invention can give stable, structurally well-defined phosphorus and sulfur containing compositions useful as additives, and which do not ordinarily yield inorganic phosphoric acids upon hydrolysis. Also, these inventive materials when reacted, e.g., with an amine, can exhibit potent dispersant-inhibitor properties.